1. Field of the Invention
This invention is related to propagation and/or feeding of optical signals via lightguide and plastic optical fibers to a photovoltaic and photocoupler devices comprising switches, MOSFET, transistors, thyristors, triacs and photo relays for use with electrical and communication devices and appliances of home, office and factory automation and communications medium.
2. Description of the Prior Art
Wired or wireless control devices are used for remotely operating AC or DC powered electrical devices and appliances such as heaters, air conditioners, motors and motorized devices, lighting and other electrical appliances in homes, apartments, offices, factories and buildings in general to switch the appliances on-off.
The switching and relay devices that are available for switching appliances on-off and/or for setting or commanding operation levels, such as dimming the lights via triacs or FET switches or via thyristors, are manually operated or are wired to a remote controller via a network, known as low voltage network. Low voltage network cannot be connected to the electrical switching device within the same wall box. Low voltage network along with the power line connection is prohibited by the electrical and building codes in most of the world countries.
The codes however delayed the introduction of low cost simple solutions for automated switching and controlling of electrical appliances and lights. Now, as the demand for reduction in electrical power consumption is prevailing and the need for a programming of the many switches and other electric and electronic devices in the buildings and factories is becoming clear, a simple solution other than low voltage wires, was needed for propagating and feeding control and communication signals to the power line switches and other control devices inside an electrical box, in which power lines are connected.
Interconnection via hardwires (copper) between or inside electrical and communication devices are similarly prevented by different ground potentials or different signaling levels or power line potentials. The use of photocouplers overcome the limitations involving different potentials at their interconnecting points. An extensive range of well known photo coupling devices are available in different packages and are offered to the electrical, electronic and communications industries throughout. In all the known photocouplers it is required that a current signal is fed to an LED or laser embedded into an IC package and other packages, or individually mounted for propagating optical signal to a pin diode or photo transistor, or other optical or photovoltaic receiving structures on the opposite side, thereby cutting any current flow between the input terminals of the transmitter and the output terminals of the receiving devices or structures.
Even though the input and the output of a photocoupler are electrically insulated, such photocouplers do not overcome the electrical and building codes limitations because the input and the output terminals of the photocoupler devices need to be hard wired and such wires or connections cannot be introduced along side or together with the AC electrical wiring systems of buildings and factories in the advanced countries of the world.
A solution for such limitation, in which relays and dimmers inside an electrical wall box are connected by lightguide or optical fiber cables, is disclosed in U.S. patent application Ser. No. 12/236,656 filed on Sep. 24, 2008 and is incorporated herein by reference.
However the lightguide solution disclosed in the above U.S. patent application Ser. No. 12/236,656 teaches the use of photo transistor and/or pin diode along with other circuits for providing one or two way communication between a controller and a switch, a relay or a dimmer device, involving number of parts and components assembled into a small packaged device that add to the manufacturing cost.
Prior arts disclosed in the above referenced U.S. application Ser. No. 12/236,656 and in the U.S. application Ser. Nos. 11/874,309 dated Oct. 18, 2007 and 11/939,785 dated Nov. 14, 2007 also teach the detection of a current flow through the switches, dimmers and power outlets for feeding to a controller current drain information such as power on or off state, or stand by and/or a specific data pertaining the current drain of a given appliance. Such data is detected via current sensor and propagated by a transmitting device such as LED through a lightguide or optical fiber cable to the controller.
The prior art in the U.S. application Ser. No. 12/236,656 discloses a single lightguide for propagating one way control commands from a controller to a switching device. It also discloses dual lightguides for propagating two way, one way for propagating commands to the switching device and in reverse direction propagating a returned data from the switching device. It further discloses the use of optical prism including half mirror structure to propagate commands to the switch and a returned data such as current drain or the load state from the switch via a single lightguide or optical fiber.
As stated above the costs to manufacture the devices disclosed in the U.S. application Ser. No. 12/236,656, including the IR or visual light transmitter and receiver and their associated circuits, parts and components into the limited space of a switching device are higher than the commonly used mechanical switches and devices and a simpler structure enabling the interconnections of optical signals via lightguide or an optical fiber at a lower cost is needed.
Similarly, the light transmission material such as silicon that fills the space between the photo transmitter and the photo receiver and its thickness, used in the well known photocouplers, represent two opposing conditions with their internal structure. The codes and rules governing insulation specify a testing procedure with very high voltages that are applied between the input and the output terminals of the photocoupler, this mandates the increase in the thickness of the silicon or the light transmission material between the LED and the photo transistor or other receiving structure. The increase in material thickness means increase in distance for the IR or visual light transmission, which reduces exponentially
  (      1          distance      2        )the light or IR reaching the optical receiver, and therefore reduces the sensitivity, the response time and increase the noise susceptibility. A simpler and improved method and apparatus are needed for photocoupling solutions.